Bladeholders for doctors and scrapers

ABSTRACT

A bladeholder for doctors, scrapers and the like has separate regions for a blade and a pressure or rocker plate. The blade can be removed, installed, or adjusted in one region without disturbing the rocker plate and associated parts in the other region. The rocker plate has constant &#39;&#39;&#39;&#39;stick-out,&#39;&#39;&#39;&#39; and can be fitted with resilient profiling devices. An improved profiling device is shown having armor cladding to prevent damage due to pressure.

United States Patent 1191 Goodnow Dec. 18, 1973 [54] BLADEHOLDERS FORDOCTORS AND 3,122,767 3/1964 Carvill 1 15/2565] X SCRAPERS 1,566,35812/1925 White 15/25651 2,962,050 11/1960 Ramberg et al. 138/127 X [75]Inv n r: Ronald R n Lelcester, 3,688,336 9/1972 Costello et a1 15/25651Mass.

[ 1 Assignee: Lodding Engineering Corporation Primary Examiner-Leon G.Machlin Auburn, MaSS- Attorney-Alfred H. Rosen et a1. [22] Filed: June26, 1972 1 1 pp 266,492 57 ABSTRACT A bladeholder for doctors, scrapersand the like has BR5651621162533) separate regions for a blade and apressure or rocker [58] Fieid 51 g 5 plate. The blade can be removed,installed, or ad- 15/256 l00/l7'4 f justed in one region withoutdisturbing the rocker 34/120 118/126 26]' 134/6 9 f plate and associatedparts in the other region. The

1012154 6 rocker plate has constant stick-out," and can be fitted withresilient profiling devices. An improved profiling device is shownhaving armor cladding to pre- [56] 'f :Zf vent damage due to pressure.

2,300,908 1 H1942 Broughton 100/174 X 23 Claims, 5 Drawing Figures 1BLADEHOLDERS FOR DOCTORS AND SCRAPERS BACKGROUND OF THE INVENTION Theart of making bladeholders for doctors and scrapers is old, yetcontinues to develop- The task of doctoring or scraping a moving worksurface, as on a roll or cylinder, for example, presents problems ofapproach to the load, operational control, and blade wear andreplacement, which continue to engage paper makers and others facing thetask. In the paper industry, doctors and scrapers are employed to cleanthe surfaces of rotating calendar rolls, drier cylinders and the like;and scrapers are used to remove a web of paper as in the manufacture ofcrepe paper (creping doctor). Scrapers (sometimes called knives) areused to remove product from drums in flakers and drum driers used toprepare dried products of various kinds (examples being foodstuffs,pharmaceuticals, chemicals, films solidified from liquids) from astarting liquid or paste.

When the surface to be doctored or scraped (working surface) is that ofamaterial soft enough to be damaged by a blade or knife approaching it atan angle that favors digging in, chipping or otherwise injuring theworking surface, it is important that the bladeholder control not onlythe angle at which the blade engages the work surface during operationbut also the angle at which the blade approaches the work surface whenbeing brought into position for operation. A blade holder which permitsthe unloaded blade in it to rock about some axis parallel to its workingedge would introduce the danger of injuring the work surface, therebyrequiring special precautions to prevent such injury.

Blades wear out in use, and many attempts have been made to extend bladelife. Attention has been given to special treatments of the workingedges of blades, to improve the lasting qualities and efficiencies ofthe working edges. Attention has also been given to making blades havingreserve body structure and adjustable holding features such that, incombination with a bladeholder incorporating cooperating adjustingfeatures, the blade can be adjusted to compensate for wearing away ofits working edge.

Much attention has been given to problems of operational control. Doctorand scraper blades are generally long thin structures approximately fourto six inches wide and extending sometimes as much as 30 feet or morefrom one end to the other, across a working surface perpendicular to thedirection of relative motion with respect to the working surface. Inpaper machinery, the long dimension of the blade is in the crossmachinedirection" (CMD). Obviously, the blade is subject to flexure in the CMD,and a high spot on the working surface, due to debris, for example, canlift the blade from the working surface in the vicinity of the highspot, and create conditions of non-uniform pressure between the bladeworking edge and the working surface in the CMD. This is a transitory,or dynamic flexure problem. There exists also a static problem of bladeflexure to accommodate roll crown and the like. An early solution tothese problems is described in U.S. Pat. No. 2,477,339 to Ljungquist,assigned to the predecessor of the assignee of the present application.Examples of the attention given to correcting these problems withyieldable displacement members are found, for example, in U.S. Pat. Nos.2,914,788 and 3,163,878, both assigned to DST Pattern and EngineeringCompanty Limited. A more recent improvement in bladeholders providinguniform pressure on the working surface is described in U.S. Pat. No.3,529,315 of Dunlap and Bedard, which is assigned to the predecessor ofthe assignee of this application. This last patent describes and claimsa bladeholder adapted to position a blade to bear against a work surfacewith substantially uniform pressure along its entire length, and ayieldable displacement member for a blade assembly which are believed toafford the most satisfactory solution yet available for this particularproblem.

The introduction of yieldable displacement members has made bladeholdersmore complicated, and has brought with it problems of protecting the.displacement members from destruction in the working environment, andduring replacement or adjustment of blades in the bladeholder, as wellas introducing complications in the installation, changing andadjustment of blades.

GENERAL NATURE OF THE INVENTION The present invention is addressed toall of the foregoing problems. A bladeholder is provided which as in theprior art, has two jaws enclosing a jaw space for receiving the backportion of a blade, and a pair of confronting lips forward through whichthe blade extends to its working edge. The holder has provision formeans, preferably resilient, arranged to apply force through a rockerplate to one side of the blade for holding the blade working edge inengagement with a working surface. The resilient means can optimally bea profiling means, and the rocker plate can be especially adapted forefficiently functioning with a profiling resilient means.

The jaw space is divided into two regions, for example by a partitionmember in the jaw space which is anchored to the bladeholder separatingone region from the other, both regions, however, communicating with thespace between the lips. The back portion of the blade is located in oneregion while the back portion of the rocker plate together with itsassociated forceapplying means is located in the second region. Meansare provided to seal the second region against entry of foreign materialthrough the lips. The blade can be installed in, removed from, or insome embodiments of the invention adjusted in, the first region withoutdisturbing the contents of the second region. The contents of the secondregion, in particular, a resilient forceapplying means, can be installedin and removed from the second region without disturbing the blade. Increping applications, where constant stick-out of the rocker plate isdesirable, embodiments of the invention which provide for independentadjustment of the blade are particularly valuable, and affordflexibility and simplicity of operation which have not heretofore beenavailable.

The arrangement of parts is such that when the blade is not loaded,namely, the working edge is out of contact with a working surface, theblade attitute, or angle is the same or approximately the same, relativeto an approaching load as the blade angle under loaded or workingcondition. To this end, the blade and rocker plate are constrainedwithin limits that are normally not reached during operation but whenreached in the absence of a load will maintain the blade at an angle, orin an attitute which closely approximates the working angle or attitude.

Resilient force-applying means for the rocker plate can be solid, as anelongated piece of rubber, or it can be a tubular member charged with afluid. If a profiling member is desired, the teachings ofabove-mentioned US. Pat. No. 3,529,315 can be incorporated. Tubularmembers charged with fluid risk loss of the fluid, shutdown and theinconvenience of needing to be changed if they are damaged. To minimizethese risks, a metal braid envelope is provided. This provision,combined with installation in a bladeholder which minimizes theoccasions for changing or adjusting the rocker-plate and resilient meanscomponents, greatly improves the utility and reliability ofbladeholders. Preferably this envelope is highly flexible, in order toavoid interference with profiling properties of the resilient meanswhile protecting it from abrasion, cuts and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-section of a firstembodiment of the invention;

FIG. 2 is a cross-section of a second embodiment of the invention;

FIG. 3 is a cross-section of a profiling resilient member;

FIG. 4 is a longitudinal end-section of the profiling member shown inFIG. 3; and

FIG. 5 is a partial plan view of a modified rocker plate.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 shows in cross section ablade holder carried by an arm 11 (i.e; doctor back) that is pivotallymounted with respect to a roll 12, the surface of which is the worksurface against which a blade 13 is intended to bear at its working edge14. As is well known, the bladeholder is an elongated structure whichmay be several feet long. The bladeholder is held to the arm by severalbolts of which only one bolt 15 is illustrated. The bladeholder iscomprised of a top piece 16 the back portion of which is bolted to thearm 11 and the forward portion of which constitutes a firstjaw member 17that terminates at its forward extremity in a first lip 18. A bottompiece 20 has a back portion 21 fastened to the top piece by severalbolts 22 and a forward portion constituting a second jaw member 23 whichterminates at its forward extremity in a second lip 24. The jaw members17 and 23 are spaced apart not only by the back portion 21 but also by aspacer member through which the bolts 22 pass into the back portion 21,and the lips 18 and 24 also are spaced apart, the jaw members rearwardlyof the lips bounding between them ajaw space 26. A platform member 28 isheld between the bottom piece back portion 21 and the spacer member 25and extends into the jaw space dividing the jaw space into two distinctregions, here in the form of a first compartment 26A bounded at one sideby the first jaw member 17 and a second compartment 268 bounded at oneside by the second jaw member 23.

A rocker plate has a rearward portion 30A located in the firstcompartment 26A, and a forward por tion 305 extending out of the firstcompartment beyond the first lip 18 and terminating in a bearing edge31. The rocker plate bears at one side (top as seen in FIG. 1) againstthe first lip 18. Resilient means 32 (to be described in detail below)is located in the first compartment 26A between the platform member 28and the opposite side (lower as seen in FIG. 1) of the rocker plate 30at the rearward portion 30A of it. Generally speaking, the resilientmeans includes an elongated flexible member which preferably has theproperty that a given pressure applied to it in one location will appearsubstantially uniformly at other locations throughout its length, andwill therefore function as a profiling means. For some applications ofthe invention, it may be satisfactory to use a simple elongatedresilient member (a spring or a rubber member, for example) which doesnot have this profiling property in a significant degree. The resilientmeans 32 will, in either case, urge the rearward portion 30A of therocker plate away from the platform member 28, and will thereby urge therocker plate to pivot around the first lip 18 in a direction tending todisplace the bearing edge 31 toward the second lip 24. Retainers in theform of short screw bolts 35 are threaded through the first jaw member17 far enough to penetrate loosely through holes 36 in the rocker plate,to hold the rocker plate in the first compartment 26A.

A thin strip 38 of buffer material is fixedly located in the jawspace inthe vicinity of the platform member, being clamped at a rearward portionbetween the spacer member 25 and the platform member 28, and extendsforward terminating at its forward edge 39 in contact with the underside (in FIG. 1) of the rocker plate 30, just forward of the first lip18. This sheet may be a sheet of steel, or other spring-like materialwhich is preferably spring-loaded to hold its forward edge 39resiliently in contact with the rocker plate, so that it aids in sealingthe first compartment 26A against the entrance of loose material duringoperation of the bladeholder. Terminating forward as it does beyond thefirst lip 18, the spring-loaded buffer strip 38 is effectivelydimensioned to cooperate with the resilient means 32 to maintain therocker plate 30 in contact with the first lip 18 when there is no bladein the second compartment 268, thereby facilitating the insertion of ablade into, and removal of the blade from the second compartment 268.

The blade 13 has spring-clips 40 attached with studs 41 along itsrearward portion within the second compartment 268. The studs retain theblade within the second compartment against the up-standing second lip24, while the spring clips bear against the underside (in FIG. 1) of theplatform member 28. This light spring action tends to retain a blade 13in the blade-holder 10 in its working attitude when it is out of contactwith the roll 12, that is, when there is no working load on the workingedge 14 of the blade. This is an important feature of the bladeholder,which prevents damage to the surface of a roll or other working surfacethat is soft enough to be damaged if the blade approaches it at an anglethat is not the correct, or at least approximately the correct workingangle.

FIG. 2 shows a second embodiment of the invention in which thebladeholder is affixed via its top piece 56 to the underside of asupporting arm or doctor back 51 by a series of bolts of which only one55 is shown. The top piece extends forward of the doctor back to a firstjaw member 57 terminating at its forward extremity in a first lip 58.The bottom piece 60 has its back portion 61 fastened to the top piece bybolts 62 which pass through a spacer member 65 into the top piece 56. Inthis embodiment the platform member 68 (corresponding to the platformmember 28 in FIG. 1) is integral with the spacer member 65, and extendsinto the jaw space 66 where it divides that space into two regionscomprised of a first compartment 66A and a second compartment 66B. Therocker plate 30, resilient means 32, retainers 35 and holes 36 in therocker plate are all similar to the like-referenced components inFIG. 1. A buffer strip 78 corresponds essentially to the buffer strip 38in FIG. 1 being in this embodiment bent to form an extended contact atits forward portion 78A with the underside of the rocker plate bothbefore and beyond contact of the rocker plate with the first lip 58. Thefirst compartment 66A and parts containedwithin it, including the bufferstrip 78, are essentially similar to the first compartment 26A and theparts contained within it in FIG. 1, in both structures and function.

The bottom piece 60 has a back portion 61 which extends forwardessentially parallel to the platform member 68, and a forward portionwhich constitutes a second jaw member 63 terminating at its forwardextremity in a second lip 64. The confronting surfaces 68.1 of theplatform member 68 and 61.1 of the back portion 61 of the bottom piece60 are each serrated or notched with a series of slots or notches 69Aand 69B, respectively, that are in register with eachother forming aladder-like series of enlarged subdivisions of the second compartment668, separated by finger-like projections 70A and 708, respectively,which extend toward but do not touch each-other.

A blade 53 has its back portion 53A in the second compartment 66A,between but not touching the confronting projections 70A, 70B, and itsforward portion 53B extending out of the holder beyond the lips 58 and64 to terminate in a working edge 54. A base plate 59 is positioned tothe rearward extremity of the blade 53, disposed transverse to thethickness of the blade and running its full length, so that in thetransverse section shown in FIG. 2 the base plate and the blade form aT." The base plate 59 generally is continuous. It has a width, acrossthe second compartment 663 which is greater than the distance betweenany pair of confronting projections 70A, 708, but somewhat less than thedistance between the bottoms of a pair of confronting slots or notches69A, 698. By sliding the blade 53 out of the second compartment 668,perpendicular to the plane of the figure, or through the lips 58 and 64,or both, the blade can be removed from the holder without disturbing therocker plate 30 or other contents of the first compartment 66A. The baseplate 59 can be removed and installed only in the directionperpendicular to the plane of the figure. With the reverse procedure,the blade can be reinserted in the holder 50 while locating the baseplate 59 in any pair of confronting slots 69A, 69B, to rest on therearward-most pair of confronting projections 70A, 708, respectively,bounding those slots, as is shown in dotted line at 59.1. In this mannerthe rearward portion 53A of the blade can be located to one of severalavailable depths in the second compartment 668, and the distance (i.e.:"stick-out) that the forward portion 538 of the blade projects beyondthe lips 58 and 64 can be adjusted, independent ofthe stick-out of therocker plate 30, which remains constant. This permits the blade to beadjusted in the holder 50 for wear, thereby extending the useful life ofa blade, as well as to accommodate blades of varying widths,

The embodiment of FIG. 2 has all the advantages and features of theembodiment of FIG. 1. In addition, this embodiment provides for separateadjustment of a blade in a holder which incorporates provisions forhydraulic profiling means, without disturbing the profiling means. Itwill be noted that, as in FIG. 1, the rocker plate 30 in FIG. 2 bears atits forward edge 31 on the top surface (in the figure) of the bladeforward of the second lip 64. The distance between the first lip 58 andthe forward edge 31 of the rocker plate 30 (i.e: the rocker platestick-out) is a constant in a given structure, which can be chosen tosuit the needs of a particular application, while the blade 53 isindependently adjustable so that the blade stick-out" (amount theforward portion 53B extends) beyond the rocker plate edge 31 isindependently variable. This feature of the invention is important forexample in creping applications, and is available independent of whetheror not a resilient force-applying means 32 is employed. With no load onthe blade, the blade will approach its load (e.g: surface of the roll12) at an angle approximately as is shown in FIG. 2, but without theslight curvature imposed by the load which is shown in the figure.

The resilient means 32 preferably has no noticeable spring rate. Ayieldable displacement member as described and claimed in U.S. Pat. No.3,529,315 may be used in place of the particular resilient means 32shown in FIGS. 1 and 2. Such a displacement member, in elongated tubularform, has the property that a given pressure applied to it in onelocation will appear substantially uniformly at other locationsthroughout its length. When incorporated as the resilient means 32 inthe present invention, it will provide a profiling feature to theinvention. Blades for doctoring, calendaring, creping, and the like,being sometimes several feet long are flexible in the direction of theworking edge. When a high spot appears on the working surface of theroll 12, tending to lift the nearby lengthwise portion of the blade fromthe roll, the blade correspondingly tends to urge the same generallengthwise portion of the rocker plate to pivot counter-clockwise aroundthe first lip, 18 or 58, of the holder. This puts an increased pressureon the corresponding lengthwise portion of the resilient means.Employing the substantially-uniform pressure property defined above, theresilient means transmits that pressure throughout its length, and thatpressure is applied via the rocker plate 30 to the blade 13 or 53, tohold down against the surface of the roll 12 the remainder of theworking edge 14 or 54. As is described in the referenced patent, suchprofiling means can be made ofa pliable tube closed at both ends andcharged with a substantially incompressible fluid, preferably a fixedvolume of non-compressible fluid to the substantial exclusion ofcompressible fluid, and the best advantages for profiling will beenjoyed if the material of the walls of the tube is relatively inelasticsuch that in the range of normal conditions of operation, it issubstantially unstretched.

The resilient means 32 shown in FIGS. 1 and 2 can also provide profilingproperties to the invention. FIGS. 3 and 4 show enlarged views of it. Anelongated tube which has or is given a generally oval cross-section ismade of a suitable plastics material, such as Teflon (DuPont trademarkfor a plastic consisting of a tetrafluoroethylene polymer). The tube canbe chosen of any suitable material (eg; rubber) in a wall thicknesshaving the desired inelastic properties. Tubes of Teflon Type FEP havingwall thickness in the range 0.015 to 0.030 inch have been used. Ametal-braid protective envelope 76 encloses the tube 75, to preventdamage to the tube-from abrasion with the surrounding metal parts whenit is installed in the bladeholder and during operation. A protectiveenvelope 76 made of highly flexible fibers will minimize interference ofthe envelope with the profiling properties of the enclosed profilingtube 75. To this end, stainless steel braid tube size 48-11-36 has beenused. After filling with a noncompressible fluid according to theabove-referenced patent, the tube 75 is sealed at its ends, by heatsealing in a known manner to provide sealed ends one of which isillustrated at 77 in FIG. 4. The metal-braid. envelope 76 is drawn overthe sealed tube end 77 and closed with a clamp 78, which can be made,for example, from a ring of as inch diameter copper tube flattened overthe overlapping metal braid.

Sensitivity of the profiling arrangement to distortion of the blade inthe cross-machine direction, as by an irregularity on the workingsurface, may be enhanced by slotting the rocker plate transversely tothe crossmachine direction, from one or both of its long edges toward orinto its median region, as is illustrated in FIG. 5. In the event aresilient means is used that does not contribute profiling properties,such as a bar of solid rubber, slotting of the rocker plate in thismanner will reduce the tendency of neighboring regions of the blade tofollow such a distortion of the blade.

When the invention is used without a resilient means 32 selectedprimarily for or with major interest in its profiling properties a barof solid rubber (not shown) as mentioned above, or an inflatable tube orhose may be used. Another alternative is a wavy spring (not shown)extending in the cross-machine direction, between the rearward portion30A of the rocker plate and the platform member 28 or 68, with its wavepeaks touching both. Such other resilient means may contribute someprofiling properties, or substantially none at aILdepending on theparticular structure that is chosen in a given installation.Bladeholders according to the invention give the user a full range ofoptions and, regardless of choise of resilient means, a blade can beinstalled, removed, and in embodiments according to FIG. 2 adjusted,without disturbing the rocker plate and resilient means subassembly.

I claim:

1. A holder for a doctor blade or the like comprising a pair of jawmembers having respective spaced-apart lips said members bounding a jawspace, a partition member in the jaw space dividing that space intofirst and second side-by-side compartments, a rocker plate having arearward lockably retained portion in the first compartment and aforward portion extending a fixed distance out of the first compartmentbeyond the lip of the jaw member bounding the first compartment, therocker plate being arranged to bear at one side against said lip andterminating at its forward portion in a bearing edge, and resilientmeans located in the first compartment between the partition member andthe rearward portion of the rocker plate; the second compartment beingfitted to receive a blade having a rearward portion located in thesecond compartment and a second portion extending out of the secondcompartment beyond both lips and said bearing edge so that said bladeduring operation will be in contact at one side with said bearing edge,said partition member and the jaw member bounding the second compartmentbeing arranged to hold removably between them the rearward portion ofsaid blade, so that a blade can be fitted into and removed from thesecond compartment independently of the contents of the firstcompartment.

2. A bladeholder according to claim 1 in which said resilient meansincorporates profiling means that includes an elongated flexible memberhaving the property that a given pressure applied to it in one locationwill appear substantially uniformly at other locations throughout itslength.

3. A bladeholder according to claim 2 in which said profiling meanscomprises a tube of flexible material closed at both ends and chargedwith a substantially incompressible fluid.

4. A bladeholder according to claim 3 in which said tube contains afixed volume of non-compressible fluid to the substantial exclusion ofcompressible fluid, and the material of the walls of said tube isrelatively inelastic such that in the range of normal conditions ofoperation it is substantially unstretched.

5. A bladeholder according to claim 3 including a tubular metal armorhaving flexibility similar to said tube substantially surrounding thetube.

6. A bladeholder according to claim 1 including a buffer strip ofgenerally rigid but flexible material having a rearward portion fixedlylocated in said jaw space in the vicinity of said partition member and aforward portion bearing against the opposite side of said rocker platein the vicinity of said first-named lip, for substantially closing saidfirst compartment to passage of material entering said jaw space betweensaid lips.

7. A bladeholder according to claim 6 in which said forward portion ofsaid buffer strip bears against said rocker plate at a location forwardof said first lip.

8. A bladeholder according to claim 1 in combination with a blade havinga rearward portion located in said second compartment and a forwardportion extending out of said second compartment beyond both said lipsand said bearing edge to a working edge, said blade being in confrontingrelation at a first side with said lip bounding the second compartmentand in contact at its other side with said bearing edge, so that whenworking force is applied to said working edge of said blade in adirection tending into said first side thereof said working force istransmitted via said rocker plate to said resilient means.

9. A combination according to claim 8 in which said resilient meansincorporates profiling means that includes an elongated flexible memberhaving the property that a given pressure applied to it in one locationwill appear substantially uniformly at other locations throughout itslength for reacting on said blade differentially along the lengththereof in response to working forces tending to deflect said bladedifferentially along said working edge.

10. A combination according to claim 9 in which said profiling meanscomprises a tube of flexible material closed at both ends and chargedwith a substantially incompressible fluid.

11. A combination according to claim 10 in which said tube contains afixed volume of non-compressible material to the substantial exclusionof compressible fluid, and the material of the walls of said tube isrelatively inelastic such that in the range of normal working forces itis substantially unstretched.

12. A combination according to claim 10 including a tubular metal armorhaving flexibility similar to said tube substantially surrounding saidtube.

13. A combination according to claim 8 including a buffer strip ofgenerally rigid but flexible material having a rearward portion fixedlylocated in said jaw space in the vicinity of said partition member and aforward portion bearing against said opposite side of said rocker platein the vicinity of said first-named lip, for substantially closing saidfirst compartment to passage of material entering said jaw space betweensaid lips.

14. A combination according to claim 8 including means in said secondcompartment for adjusting the distance said blade extends out of saidsecond compartment.

15. A bladeholder according to claim 1 including adjustable bladesupport means between a side of said platform member and the confrontingrearward portion of said second jaw member that bounds said secondcompartment.

16. A bladeholder according to claim in combination with a blade havinga rearward portion located in said second compartment and a forwardportion extending out of said jaw space beyond both said second namedlip and said bearing edge to a working edge, and means at said rearwardportion for cooperating with said adjustable support means to adjust theextension of said blade out of said jaw space.

17. A bladeholder according to claim 16 wherein said blade is inconfronting relation at a first side with said second named lip and incontact at its other side with said bearing edge, so that when workingforce is applied to said working edge of said blade in a directiontending into said first side thereof said working force is transmittedvia said rocker plate to said resilient means.

18. A combination according to claim 8 including slotted adjustmentmeans in said second compartment to adjust the distance said forwardportion of said blade extends beyond said second lip.

19. A combination according to claim 18 in which adjustment meansincludes a rigid member confined by the slotted means and transverselydisposed in said second compartment at the back edge of the rearwardportion of said blade.

20. A bladeholder adapted to position a blade to bear against a worksurface comprising first and second jaw members terminating in first andsecond respective spaced-apart lips and rearwardly of said lips boundinga jaw space between them, a platform member fixed in said jaw spacebetween said members dividing said jaw space into a first compartmentbounded at one side by said first jaw member and a second compartmentbounded at one side by said second jaw member, a rocker plate having arearward portionlocated in said first compartment and a forward portionextending from said bladeholder a constant distance beyond said firstlip and terminating in a bearing edge, means for causing said rockerplate bear at one side against said first lip, a buffer strip having arearward portion fixed in said jaw space in the vicinity of saidplatform member and a forward portion bearing against the opposite sideof said rocker plate for closing the first compartment to passage ofmaterial entering said jaw space between saidlips, a blade having arearward portion located in said second compartment and a forwardportion extending out of said second compartment beyond both said secondlip and said bearing edge to a working edge, said blade being inconfronting relation at a first side with said second lip and in contactat its other side with said bearing edge, and means in said secondcompartment for adjusting the distance said blade extends out of saidsecond compartment, independently of said rocker plate.

21. A bladeholder according to claim 20 in which said platform meanscomprises a rigid member traversing said jaw space dividing said firstand second regions into respective first and second compartments, saidadjusting means being disposed between said rigid member and therearward portion of said second jaw member that bounds said secondregion.

22. A bladeholder according to claim 21 including pairs of confrontingslots in said rigid member and said second jaw member and an elongatedbase member slidably engaged in one such pair of slots for supportingand locating the rearward portion of said blade in said second region.

23. A bladeholder according to claim 21 including a rigid membertransversely disposed in said second region for locating said rearwardportion of said blade therein.

(22 53 UNITED STATES PATENT OFFICE QERTWICATE 0F CORRECTION Patent: No.3,773, 1 Dated n gg 1913 Inventofls) Ronald F. Goodnow It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 5, line 14, delete "structures" and insert --structureline 23,delete "eachother" and insert --each other-- line 27, delete"each-other" and insert --each other-- Column 6, line 31, delete"calendaring" and insert -calendering-- Column- 10, line 11, after"plate" insert --to- Signed and Scaled this eighth Day of June 1976[SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Atresting Officer I Commissioneroj'Parems and Trademarks

1. A holder for a doctor blade or the like comprising a pair of jawmembers having respective spaced-apart lips said members bounding a jawspace, a partition member in the jaw space dividing that space intofirst and second side-by-side compartments, a rocker plate having arearward lockably retained portion in the first compartment and aforward portion extending a fixed distance out of the first compartmentbeyond the lip of the jaw member bounding the first compartment, therocker plate being arranged to bear at one side against said lip andterminating at its forward portion in a bearing edge, and resilientmeans located in the first compartment between the partition member andthe rearward portion of the rocker plate; the second compartment beingfitted to receive a blade having a rearward portion located in thesecond compartment and a second portion extending out of the secondcompartment beyond both lips and said bearing edge so that said bladeduring operation will be in contact at one side with said bearing edge,said partition member and the jaw member bounding the second compartmentbeing arranged to hold removably between them the rearward portion ofsaid blade, so that a blade can be fitted into and removed from thesecond compartment independently of the contents of the firstcompartment.
 2. A bladeholder according to claim 1 in which saidresilient means incorporates profiling means that includes an elongatedflexible member having the property that a given pressure applied to itin one location will appear substantially uniformly at other locationsthroughout its length.
 3. A bladeholder according to claim 2 in whichsaid profiling means comprises a tube of flexible material closed atboth ends and charged with a substantially incompressible fluid.
 4. Abladeholder according to claim 3 in which said tube contains a fixedvolume of non-compressible fluid to the substantial exclusion ofcompressible fluid, and the material of the walls of said tube isrelatively inelastic such that in the range of normal conditions ofoperation it is substantially unstretched.
 5. A bladeholder according toclaim 3 including a tubular metal armor having flexibility similar tosaid tube substantially surrounding the tube.
 6. A bladeholder accordingto claim 1 including a buffer strip of generally rigid but flexiblematerial having a rearward portion fixedly located in said jaw space inthe vicinity of said partition member and a forward portion bearingagainst the opposite side of said rocker plate in the vicinity of saidfirst-named lip, for substantially closing said first compartment topassage of material entering said jaw space between said lips.
 7. Abladeholder according to claim 6 in which said forward portion of saidbuffer strip bears against said rocker plate at a location forward ofsaid first lip.
 8. A bladeholder according to claim 1 in combinationwith a blade having a rearward portion located in said secondcompartment and a forward portion extending out of said secondcompartment beyond both said lips and said bearing edge to a workingedge, said blade being in confronting relation at a first side with saidlip bounding the second compartment and in contact at its other sidewith said bearing edge, so that when working force is applied to saidworking edge of said blade in a direction tending into said first sidethereof said working force is transmitted via said rocker plate to saidresilient means.
 9. A combination according to claim 8 in which saidresilient means incorporates profiling means that includeS an elongatedflexible member having the property that a given pressure applied to itin one location will appear substantially uniformly at other locationsthroughout its length for reacting on said blade differentially alongthe length thereof in response to working forces tending to deflect saidblade differentially along said working edge.
 10. A combinationaccording to claim 9 in which said profiling means comprises a tube offlexible material closed at both ends and charged with a substantiallyincompressible fluid.
 11. A combination according to claim 10 in whichsaid tube contains a fixed volume of non-compressible material to thesubstantial exclusion of compressible fluid, and the material of thewalls of said tube is relatively inelastic such that in the range ofnormal working forces it is substantially unstretched.
 12. A combinationaccording to claim 10 including a tubular metal armor having flexibilitysimilar to said tube substantially surrounding said tube.
 13. Acombination according to claim 8 including a buffer strip of generallyrigid but flexible material having a rearward portion fixedly located insaid jaw space in the vicinity of said partition member and a forwardportion bearing against said opposite side of said rocker plate in thevicinity of said first-named lip, for substantially closing said firstcompartment to passage of material entering said jaw space between saidlips.
 14. A combination according to claim 8 including means in saidsecond compartment for adjusting the distance said blade extends out ofsaid second compartment.
 15. A bladeholder according to claim 1including adjustable blade support means between a side of said platformmember and the confronting rearward portion of said second jaw memberthat bounds said second compartment.
 16. A bladeholder according toclaim 15 in combination with a blade having a rearward portion locatedin said second compartment and a forward portion extending out of saidjaw space beyond both said second named lip and said bearing edge to aworking edge, and means at said rearward portion for cooperating withsaid adjustable support means to adjust the extension of said blade outof said jaw space.
 17. A bladeholder according to claim 16 wherein saidblade is in confronting relation at a first side with said second namedlip and in contact at its other side with said bearing edge, so thatwhen working force is applied to said working edge of said blade in adirection tending into said first side thereof said working force istransmitted via said rocker plate to said resilient means.
 18. Acombination according to claim 8 including slotted adjustment means insaid second compartment to adjust the distance said forward portion ofsaid blade extends beyond said second lip.
 19. A combination accordingto claim 18 in which adjustment means includes a rigid member confinedby the slotted means and transversely disposed in said secondcompartment at the back edge of the rearward portion of said blade. 20.A bladeholder adapted to position a blade to bear against a work surfacecomprising first and second jaw members terminating in first and secondrespective spaced-apart lips and rearwardly of said lips bounding a jawspace between them, a platform member fixed in said jaw space betweensaid members dividing said jaw space into a first compartment bounded atone side by said first jaw member and a second compartment bounded atone side by said second jaw member, a rocker plate having a rearwardportion located in said first compartment and a forward portionextending from said bladeholder a constant distance beyond said firstlip and terminating in a bearing edge, means for causing said rockerplate bear at one side against said first lip, a buffer strip having arearward portion fixed in said jaw space in the vicinity of saidplatform member and a forward portion bearing against the opposite sideof said rocker plate for closing the first compartment to passage ofmateriaL entering said jaw space between said lips, a blade having arearward portion located in said second compartment and a forwardportion extending out of said second compartment beyond both said secondlip and said bearing edge to a working edge, said blade being inconfronting relation at a first side with said second lip and in contactat its other side with said bearing edge, and means in said secondcompartment for adjusting the distance said blade extends out of saidsecond compartment, independently of said rocker plate.
 21. Abladeholder according to claim 20 in which said platform means comprisesa rigid member traversing said jaw space dividing said first and secondregions into respective first and second compartments, said adjustingmeans being disposed between said rigid member and the rearward portionof said second jaw member that bounds said second region.
 22. Abladeholder according to claim 21 including pairs of confronting slotsin said rigid member and said second jaw member and an elongated basemember slidably engaged in one such pair of slots for supporting andlocating the rearward portion of said blade in said second region.
 23. Abladeholder according to claim 21 including a rigid member transverselydisposed in said second region for locating said rearward portion ofsaid blade therein.